This new runtime marks a significant update to App Engine and was enabled by new open source software that we recently released: gVisor and FTL.

Python, straight from the source

Running Python 3.7 on App Engine and Cloud Functions required us to fundamentally rethink our infrastructure. Traditionally, meeting Google Cloud’s security requirements meant that we had to run a modified version of the Python interpreter. However, using a modified interpreter constrained some language features and only allowed us to support a limited set of whitelisted Python libraries.

Thanks to gVisor, a container sandbox that provides improved security and process isolation, we can now run the unmodified Python 3.7.0 interpreter. We’ve done extensive testing to make sure Python 3.7 is compatible with gVisor. As part of our compatibility testing, we run Python’s full suite of language tests, and tests for Python packages that are popular on PyPI. We’re committed to ensuring that everything you’ve come to know and love about Python is supported on our platform.

Seamless deployments

Most importantly, this change in our infrastructure makes it easier to take advantage of Python’s vast ecosystem. As a developer, you just add project dependencies to a requirements.txt file and deploy.

During deployment, FTL, a tool for building containers, fetches dependencies listed in your requirements.txt file and installs them alongside your app or function. FTL also includes a short-lived dependency cache, which speeds up repeated deployments if no changes are detected in your requirements.txt file. This is particularly useful if you find just need to re-deploy because you found a typo.

Keeping up with the Pythonistas

In making these changes, we also decided to expand the list of system packages that are included with each runtime’s Ubuntu 18.04 distribution. We think that will make life just a little bit easier for developers working with the latest release of Python.

Looking forward, we’re excited about how these changes will allow us to keep up with the Python community’s progress as they release new versions and libraries. Please let us know what you think and if you run into any challenges.

You can learn more about how to get started with it on App Engine and Cloud Functions in our documentation. We can’t wait to see what you build with Python 3.7.